Phthalonitrile-based precursors, high-temperature resin, and composite compositions thereof

Abstract

A composition includes at least one bonded alkene-terminated polyphenol reacted with 3-phthalonitrile. Methods of manufacturing the composition are disclosed, along with various polymers, composites, and articles, among others.

Description

PHTHALONITRILE-BASED PRECURSORS, HIGH-TEMPERATURE RESIN, AND COMPOSITE COMPOSITIONS THEREOFCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to and the benefit of U.S. Provisional Application No. 63 / 556,924, filed on February 23, 2024, and U.S. Provisional Application No. 63 / 556,925, filed on February 23, 2024, the disclosures of which are incorporated herein by reference in their entirety.STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH AND DEVELOPMENT

[0002] This invention was made with government support under Contract No. FA8650-21-2-5028 awarded by the United States Air Force (USAF). The government has certain rights in the invention.FIELD

[0003] The present disclosure relates to monomer and polymer compositions for composite materials, and more particularly to bio-enabled monomer precursors, and bio-enabled polymers having high temperature capability, high char yield, and improved processability.BACKGROUND

[0004] The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.

[0005] A variety of polymers are available for uses in applications such as aerospace, which require lightweight materials with elevated service temperatures. Many lightweight materials for aerospace applications include fiber reinforced polymer composites, wherein the polymer may be a thermoset or a thermoplastic. Further, the fibers may be continuous or discontinuous, and the composite material may come in a variety of forms such as woven or unidirectional, among others.

[0006] Most polymers are derived from petroleum refining, which is a concern due to climate change and the environmental pollution from petroleum production. To address this concern, bio-enabled polymers have been developed that are made from renewable biomass materials such as cellulose, lignin, starch, pectin, chitin, and xylan.

[0007] The development of bio-enabled polymers, having chemical structures discovered in, duplicated or derived from, or produced in whole or in part through biological systems, with better comprehensive properties, showing more competitiveness than their petroleum-based counterparts in high-tech fields, is an increasing trend but also a formidable challenge. One area of interest is bio-enabled phthalonitrile precursors based on naturally occurring Magnolia species, such as Magnolia Officinalis, which include magnolol, honokiol and combinations thereof. After curing, both magnolol- and honokiol-based resins exhibit glass transition temperatures higher than 400°C and 5% weight loss temperatures above 450°C. These properties are generally superior to those of petroleum-based resins, and are desirable for the needs of certain aerospace and other applications. In addition, the particular chemical structural features that are present in such bio-enabled resins may be replicated, in the same or similar form, even in substances derived from petroleum products, in order to obtain superior performance characteristics. In such cases, the improved performance is considered "bio-enabled," and as used herein this term should be construed to mean the composition is inspired by, or an imitation, at the level of chemical structure, of a biologically derived substance.

[0008] In particular, Magnolia is a large genus of flowering plant species. Magnolia Officinalis is a species of Magnolia native to the mountains and valleys of China. Magnolol is a compound that is extracted from the bark of Magnolia Officinalis. Magnolol is an organic compound that is classified as a lignan, a class of low molecular weight monomers found in plants. In addition to magnolol, related lignans occur in the extracts including honokiol, which is an isomer of magnolol.

[0009] Magnolol and honokiol can be employed as platform chemicals to impart excellent performance to bio-enabled polymers for great promise in cutting- edge applications. However, at present magnolol and honokiol are known to be reacted with 4-nitrophthalonitrile to form a precursor that is subsequently separated and purified, optionally solidified and sifted for storage, liquified, optionally mixed with curatives, additives, or reinforcements, formed into a desired shape, and then solidified through polymerization. The use of 4-nitrophthalonitrile creates intrinsic limitations in the ability to carry out these processes in an efficient manner under conditions needed for industrial production while simultaneously realizing the high levels of thermal and mechanical performance in finished articles. At present, there exists no straightforward method of systematically improving the ability to carry outthese processes in an efficient manner under conditions needed for industrial production while simultaneously realizing the high levels of thermal and mechanical performance in finished articles.

[0010] The present disclosure addresses these challenges related to bio-enabled monomers which are used to form bio-enabled polymers in advanced, high temperature applications such as aerospace.SUMMARY

[0011] This section provides a general summary of the disclosure and is not a comprehensive disclosure of its full scope or all of its features.

[0012] Magnolia Officinalis extracts (including magnolol or honokiol or mixtures thereof) contain a set of distinctive chemical features that may be synergistically combined with other specific features during reaction with phthalonitriles to provide advantages in processing and performance. The distinctive features include 1 ) a terminal alkene group, which for purposes of the present disclosure is defined as a molecular fragment, or radical, described with the chemical formula =CH2 wherein this fragment is chemically bonded to another carbon atom via the linking double bond, 2) bonding of the terminal alkenyl group to a phenol group within the same molecule, wherein the phenol group is described by the formula -Ar- OH, wherein Ar represents any aromatic ring structure. When such a connection between the phenol and terminal alkene is present, the structure is referred to in the present disclosure as “bonded alkene-terminated”. For example, magnolol is described in the present disclosure as a “bonded alkene-terminated phenol”. Other example of bonded alkene-terminated phenols include 4-vinylphenol, diallyl Bisphenol A, and chavibetol. Examples of similar compounds that are not bonded alkene- terminated phenols are isoeugenol (not a terminal alkene) and 4-methylstyrene (not a phenol). 3) steric hindrance of the phenol, which for the purposes of the present disclosure is defined as the attachment via chemical bond, at one or more positions in a configuration ortho- to the oxygen of the phenol fragment, of any atom except hydrogen, wherein the attached atom may be further bonded to other atoms. Examples of such bonded atoms and groups include an allyl group, as in diallyl bisphenol A, or a phenyl ring, as in magnolol. For the purposes of the present disclosure, the term “bonded alkene-terminated, sterically hindered phenol” is defined to represent any phenol wherein all three of the above conditions are fulfilled. For example, chavibetolis a “bonded alkene-terminated, sterically hindered phenol” whereas 4-vinylphenol is not (no steric hindrance of the phenol).

[0013] When the above three structural features are simultaneously present in bonded alkene-terminated, sterically hindered phenols, reaction with phthalonitriles that also feature steric hindrance around one or more nitriles in the resulting adduct provides novel compositions that exhibit beneficial processing and performance characteristics not observed when these specific combinations are not employed. Because these underlying chemical features drives properties and performance, similar benefits are realized whenever the structures are combined synergistically via chemical reaction. For the following discussion, Magnolia Officinalis extracts are utilized as one example in order to illustrate how these benefits are created. A similar, though not necessarily identical, set of benefits is realized when another bonded alkene-terminated polyphenol, such as 2,2 ' -bis(3-allyl-4- hydroxyphenyl)isopropylidene or 4,4'-Sulfonylbis[2-(prop-2-en-1-yl)phenol], is used in place of the Magnolia Officinalis extract. In this embodiment, a polyphenol is defined as an organic compound containing two or more phenolic hydroxyl groups. A sterically hindered polyphenol is defined as a polyphenol where at least one of the phenolic groups is sterically hindered.

[0014] Magnolia Officinalis extracts (including magnolol or honokiol or mixtures thereof) are reacted with 3-phthalonitrile to create compositions. The compositions include monomers or precursors that form polymers or cured resins, prepregs, or composites with extremely high Tg, wet Tg, char yield, and excellent processability. Further, the compositions may be partially cured (i.e., contain residual unreacted polymerizable groups) or fully cured. The resins may be cured via known methods including via exposure to elevated temperatures, energetic radiation such as ultraviolet or electron beams, or radio frequency or microwave beams. The compositions formed from the reaction of Magnolia Officinalis extracts (including magnolol or honokiol or mixtures thereof) are reacted with 3-phthalonitrile include monomers, precursors, prepregs, or composites that allow for high char yields during subsequent decomposition, facilitating the formation of pyrolized or graphitized materials with beneficial high-temperature performance. The compositions further include precursors, monomers, polymers, prepregs, or composites can be formed into articles for use in applications such as aerospace.

[0015] 3-phthalonitrile herein refers to a substance containing a phthalonitrile molecular fragment in a configuration wherein the phthalonitrile fragment is chemically bonded to another molecular fragment in an ortho- position relative to at least one nitrile group in the phthalonitrile fragment. An example of 3-pthalonitrile is 3- nitrophthalonitrile, shown in FIG. 1.

[0016] The mixtures of magnolol and honokiol can be in any ratio, such as a ratio of 1 part by weight magnolol to 99 parts by weight honokiol, 20 parts by weight magnolol to 80 parts by weight honokiol, 40 parts by weight magnolol to 60 parts by weight honokiol, 60 parts by weight magnolol to 40 parts by weight honokiol, 80 parts by weight magnolol to 20 parts by weight honokiol, or 99 parts by weight magnolol to 1 part by weight honokiol.

[0017] Further, the resulting precursors can undergo thermal addition curing without the addition of traditional curing agents such as curing agents containing an amino or hydroxy group. The production and processability of the resulting bioenabled thermoset system can be effectively improved by magnolol and honokiol or mixtures thereof to form the precursors. After curing, the phthalonitrile resins derived from magnolol, honokiol and mixtures thereof outperformed other bio- and petroleumbased counterparts in thermal stabilities, including a Tgof more than 400°C and a 5% weight loss temperature of more than 450°C.

[0018] In addition, the present disclosure includes 1 D (e.g., filament), 2D (e.g., prepreg), and 3D (e.g., needle felted) composites and ceramic compositions fabricated from the Magnolia Officinalis (magnolol and honokiol or mixtures thereof) and 3-phthalonitrile reaction product precursors.

[0019] Resin and composite compositions may also be fabricated from Magnolia Officinalis extracts (magnolol and honokiol or mixtures thereof) and one or more other monomers, such as magnolia 4-nitrophthalonitrile adducts, various 3- and 4-phthalonitrile adducts, propargyl ethers, cyanate esters, among others. Resin and composite compositions may further include additives, such as phenolic and aminofunctionalized compounds, as well as transition metal catalysts for lower cure, alumina and silica particles for toughening, or boron nitride, boron carbide, silicon carbide, and carbon micro- and nanostructures. The compositions derived from the reaction of Magnolia Officinalis extracts (including magnolol or honokiol or mixtures thereof) and 3-phthalonitrile may further include reaction products with a fraction of other building blocks, including but not limited to 4-nitrophthalonitrile, allyl and propargyl halides,benzyl halides, cyanogen halides, epihalohydrins, aldehydes, and alkyl dihalides, among others.

[0020] In one form of the present disclosure, a composition is provided that comprises at least one bonded alkene-terminated polyphenol reacted with 3- phthalonitrile. In variations of this composition, which may be implemented individually or in any combination: the at least one bonded alkene-terminated polyphenol is sterically hindered; a functional group of the at least one bonded alkene-terminated polyphenol is an allyl group; the at least one bonded alkene-terminated polyphenol comprises magnolol, honokiol, or a mixture of magnolol and honokiol; at least one of the magnolol, the honokiol, or the mixture of magnolol and honokiol comprises magnolia species extracts; the at least one bonded alkene-terminated polyphenol comprises 2,2'-bis(3-allyl-4-hydroxyphenyl)isopropylidene and / or 4,4’-sulfonylbis[2- (prop-2-en-1-yl)phenol]; the 3-phthalonitrile comprises 3-nitrophthalonitrile; the at least one bonded alkene-terminated polyphenol is reacted with less than about 0.95 equivalents of 3-phthalonitrile; the at least one bonded alkene-terminated polyphenol is further reacted with a molecule group selected from the group consisting of 4- nitrophthalonitrile, allyl and propargyl halides, alkyl halides, alkenyl halides, alkynyl halides, aryl halides, benzyl halides, aryl dihalides, and alkyl dihalides; the at least one bonded alkene-terminated polyphenol comprises magnolol and honokiol, and wherein an amount of the magnolol is from 40 to 60 parts by weight, and an amount of the honokiol is in an amount from 40 to 60 parts by weight; at least one substance is selected from the group consisting of magnolia 4-nitrophthalonitrile adducts, phenolic adducts of 3-nitrophthalonitrile and / or 4-nitrophthalonitrile, propargyl ethers, epoxies, benzoxazines, maleimides, and cyanate esters; at least one additive is selected from the group consisting of phenolic and amino-functionalized compounds, transition metal catalysts, and carbon and inorganic micro- and nano-structures; a ceramic and / or graphitic composite material comprising the composition comprises a ceramic that has been pyrolized, carbonized, and / or graphitized; an article comprising the ceramic and / or graphitic composite material is provided; a partially or fully cured polymer comprising the composition and its variations is provided; the partially or fully cured polymer has a char yield of at least about 75%; the partially or fully cured polymer contains residual unreacted polymerizable groups; an article comprising the partially or fully cured polymer is provided; a composite prepreg material comprising the composition is provided; a reinforced composite material comprising the compositionis provided; and a filament material comprising the composition is provided.

[0021] In another form of the present disclosure, a method of manufacturing the composition and its variations set forth above is provided. In this method, the at least one bonded alkene-terminated polyphenol is chemically reacted with 3-phthalonitrile to form a mixture. In variations of this method, which may be implemented individually or in any combination: (a) the mixture is heated, the mixture comprising at least one bonded alkene-terminated, sterically hindered polyphenol and 3-nitrophthalonitrile, to a temperature from about 20°C to about 120°C and (b) the mixture is cooled to a temperature from about -20°C to 100°C to form a precipitate; the mixture comprises at least one bonded alkene-terminated, sterically hindered polyphenol and 3-nitrophthalonitrile, and the mixture is heated to a temperature from about 40°C to about 85°C, and cooled to a temperature from about 0°C to 50°C to form a precipitate; the mixture comprises at least one bonded alkene-terminated, sterically hindered polyphenol and 3-nitrophthalonitrile, and the mixture is heated to a temperature from about 60°C to about 80°C, and cooled to a temperature from about 10°C to 40°C to form a precipitate.

[0022] In yet another form of the present disclosure, a method of manufacturing the partially or fully cured polymer as set forth above is provided, wherein the partially or fully cured polymer is reacted without use of a curing agent.

[0023] Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.DRAWINGS

[0024] In order that the disclosure may be well understood, there will now be described various forms thereof, given by way of example, reference being made to the accompanying drawings, in which:

[0025] FIG. 1 is a diagram illustrating the reaction of Magnolia officinalis extracts (magnolol and honokiol or mixtures thereof) with 3-nitrophthalonitrile to form resin precursors;

[0026] FIG. 2 is a molecular diagram illustrating magnolol and honokiol precursors fully functionalized with 3-nitrophthalonitrile;

[0027] FIG. 3 is a molecular diagram illustrating a mixture of magnolol and honokiol fully functionalized with 3-nitrophthalonitrile, along with magnolol and honokiol that are under functionalized with 3-nitrophthalonitrile, produced by means of altering the ratio of 3-nitrophthalonitrile to extracts and adjusting reaction conditions;

[0028] FIG. 4 is a molecular diagram illustrating honokiol fully functionalized with 3-nitrophthalonitrile;

[0029] FIG. 5A is a molecular diagram illustrating magnolol and honokiol reacted with 4-nitrophthalonitriles;

[0030] FIG. 5B is a molecular diagram illustrating magnolol and honokiol reacted with 3-nitrophthalonitriles; and

[0031] FIG. 6 is a differential scanning calorimetry plot illustrating thermal property differences between Magnolia Officinalis reacted with 3- nitrophthalonitrile and Magnolia Officinalis reacted with 4-nitrophthalonitrile.

[0032] The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way.DETAILED DESCRIPTION

[0033] The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features.

[0034] Although phthalonitrile resins have excellent thermal and mechanical properties, harsh curing processes, including a narrow processing window and a long curing time represent major challenges. Changes in chemical structures have been developed to improve these problems including the design of new phthalonitrile precursors and curing agents. Precursors with low melting or softening points enable a wider range of available processing temperatures, that is, they widen the processing window, and thereby improve the curing process of phthalonitrile resin, but also create performance trade-offs due to lowered glass transition temperatures (see, for instance, Dominguez, D. D. and Keller, T. M., “Low-melting Phthalonitrile Oligomers: Preparation, Polymerization, and Polymer Properties”, High Performance Polymers, Vol. 18, Issue 3, 2006, pp. 283-304). Compositions based on Magnolia Officinalis derivatives and certain phthalonitriles such as 4-nitrtophthalonitrile are known; however, such ingredients provide polymers which may exhibit unfavorableseparation, purification, solidification, sifting, and subsequent liquification and mixing characteristics for industrial use. Subsequently, an increase in impurity content in these materials may lead to defects in the resulting composites. See Weng, Z. et al., Polymer, 2021 , 226, 123814, which is incorporated in its entirety herein by reference. There is no known literature reporting on the use of Magnolia Officinalis extracts as raw materials reacted with 3-phthalonitrile to form the precursor that is subsequently polymerized to form a bio-enabled polymer having outstanding thermal and mechanical properties.

[0035] The inventors have discovered an unexpected bio-enabled precursor composition, and a bio-enabled polymer that achieves improved processing, while maintaining desirable cure rates and performance characteristics.

[0036] In particular, the present disclosure provides a bio-enabled precursor composition, which results in cured bio-enabled resins with extremely high Tg(glass transition temperature), wet Tg, char yield, and excellent processability characteristics such as ease of separation and purification, low viscosity, and a wide processing window. Unexpectedly, as described herein, compositions comprising bonded, alkene-terminated phenols reacted with 3-phthalonile exhibit higher char yields than analogous compositions comprising 4-phthalon itrile as a reactant. A variety of material forms are contemplated with the bio-enabled polymer, such as by way of example, filaments, prepreg, and reinforced (e.g., 3-D) composite materials, along with carbon-fiber reinforced ceramic or carbonaceous materials.

[0037] In the present disclosure, magnolol (3’,5-diallyl-[1 , 1 ’-biphenyl]- 2,4’-dioxy) and its isomer honokiol (5,5’-diallyl-[1 ,1 ’-biphenyl]-2,2’diol) and mixtures thereof are used as platform chemicals for the preparation of a bio-enabled phthalonitrile resin. Magnolol and its isomer honokiol and mixtures thereof are reacted with a 3-phthalonitrile to form the precursor composition used to produce bio-enabled phthalonitrile resins. The use of magnolol and honokiol as raw materials afford potential advantages, including the following: First, the biphenyl structure in the chemicals can enhance the thermal stabilities of resins. Second, the magnolol and honokiol monomers activate the phthalonitrile resin so as to enable curing without the addition of an additional curing agent, such as aromatic amines, phenols, acids, and transition metal complexes. In particular, the presence of an allyl group (an example of a bonded terminal alkene) in the magnolol and honokiol monomers contributes to creating additional reaction pathways that enable the phthalonitrile resin to cure andgenerate additional cross-linked sites within the cured polymer network without the need to add an external curing agent. The additional cross-linked sites are of particular benefit for phthalonitriles derived from sterically hindered phenols, where curing reactions involving residual phenols, or reactions involving phthalonitrile groups packed closely to the parent phenol fragment, proceed with difficulty. Third, the combination of processability and thermomechanical properties for the resins and resultant composites is improved and can also be adjusted by changing the proportion of magnolol and honokiol.

[0038] Referring to FIG. 1 , the bio-enabled precursor according to the teachings of the present disclosure includes Magnolia Officinalis extract (magnolol and honokiol or a combination thereof), and 3-phthalonitrile (C8H3N3O2) molecules, as shown. The routes for preparing bio-based phthalonitrile resins are shown in FIG. 1.

[0039] Referring to FIG. 2, the molecular diagram illustrating magnolol and honokiol precursor compositions fully functionalized with 3-nitrophthalonitrile is shown. This precursor composition generally requires that a curing agent be added to form a resin. This mixture of precursor compositions is referred to herein as Precursor A.

[0040] Referring to FIG. 3, the bio-based precursors according to the teachings of the present disclosure include magnolol and honokiol reacted with 3- phthalonitrile (C8H3N3O2) molecule groups. This figure shows the precursors that are fully functionalized by reaction with 3-nitrophthalonitrile and corresponding precursors that are not fully functionalized by reaction with 3-nitrophthalonitrile. The partially functionalized precursors may be formed, for example, by reacting magnolol and honokiol or combinations thereof with less than about 0.95 equivalents of 3- nitrophthalonitrile. Notably, the under functionalized precursors (not fully functionalized) have exposed OH groups. This mixture of precursors is referred to herein as Precursor B.

[0041] Referring to FIG. 4, a molecular diagram illustrates honokiol fully functionalized with 3-nitrophthalonitrile. This precursor is referred to herein as Precursor C.

[0042] Referring to FIGS. 5A and 5B, molecular diagrams illustrate structural differences between magnolol and honokiol reacted with 4-phthalonitriles and 3-phthalonitriles. Highlighted in FIG. 5A is a carbon atom that separates ether and cyano groups in 4-phthalonitriles (which is not the case in the case of 3-phthalonitriles).

[0043] The properties of the bio-enabled phthalonitrile resins are influenced by the use of the magnolol and honokiol isomers or combinations thereof. Notably, the precursor composition formed by reacting magnolol and honokiol respectively with 3-phthalonitrile have melting points of 155°C and 120°C, respectively, due to their different molecular structure symmetry. Comparatively, the corresponding characteristic for the reaction of magnolol and 4-nitrophthalonitrile is 176.5°C. Similarly, Magnolia Officinalis extract reacted with 3-nitrophthalonitrile can be isolated as a semi-crystalline solid with a glass transition temperature of 36°C and a melting point of 131 °C, whereas the respective adduct with 4-nitropthalonitrile is an amorphous material with a glass transition temperature of 30°C (see, FIG. 6). The inventive precursors advantageously can undergo thermal curing to form a solid polymer network. A wide processing window allows time for the liquified resin to assume a desired shape prior to solidification under conditions favorable for composite production. The composites materials so produced may further comprise reinforcements such as quartz, glass fiber, particulate silica, carbon fiber, basalt fibers, or other reinforcements, or they may comprise mixtures of fibers such as the Kevlar® or Nomex® brand aramids, or fillers such as talc or mica. Based on the results, the inventive compositions provide exciting opportunities for new high-performance bioenabled thermoset polymers.

[0044] One form of the present disclosure is a monomer derived from the reaction of magnolol and honokiol or a combination thereof and 3-phthalonitrile molecule groups. These precursor compositions provide bio-enabled materials with superior properties, particularly compared to precursors derived from the reaction of magnolol and honokiol or a combination thereof and 4-phthalonitrile molecule groups, in part because the chemical structure of the present disclosure affects the crystal packing and characteristics of the substance. These differences in crystal characteristics consequently affect the isolation, purity, and melting characteristics of the monomer, which can lead to differences in performance. In the field of high- performance polymers made from similar thermosetting networks, it has been documented that small changes in chemical structure lead to important changes in melting characteristics that are difficult to predict in advance using known methods. See, for example, Ghiassi, K. B. et al., “Insights into Melting Behavior of Propyl- Bridged Di(cyanate ester) Monomers through Crystal Packing, ThermalCharacterization, and Computational Analysis”, Crystal Growth and Design, Vol. 18, Issue 2, 2018, pp. 1030-1040.

[0045] Additional monomers may also be used to form portions of building blocks for the bio-enabled polymer including, 4-nitrophthalonitrile, alkyl halides, alkenyl halides, alkynyl halides, aryl halides, the respective diahalides and polyhalides, allyl and propargyl halides, benzyl halides, cyanogen halides, epihalohydrins, aldehydes, and alkyl dihalides, among others.

[0046] The bio-enabled polymer may also be formed from mixtures of magnolia 3-nitrophthalonitrile with other precursors, such as by way of example magnolia 4-nitrophthalonitrile, various 4- and 3-phthalonitriles, propargyl ethers, epoxies, benzoxazines, cyanate esters, anhydrides, amines, imides, or compounds containing phenyl ethynyl groups, among others.

[0047] Further, additives can be reacted with the precursors or blended with the polymers, such as by way of example phenolic and amino-functionalized compounds for hardening, transition metal catalysts for lower cure temperatures, and particles such as fillers, among others. Examples of particles include carbon black, expanded graphite, solid coal tar pitch, and other highly carbonaceous substances in particulate form for char yield enhancement. Further examples of particles may include alumina, silica, boron nitride, boron carbide, carborane nanostructures, silicate nanostructures such as oligomeric silsesquioxanes, silicon nitride, and / or silicon carbide for toughening and improved high temperature performance.

[0048] Further disclosed are methods for producing or manufacturing the reaction product of bonded alkene-terminated and, optionally, sterically-hindered polyphenols and 3-phthalonitriles, through means of a chemical reaction. The chemical reaction may include the steps of heating a mixture of polyphenols and 3- phthalonitriles, followed by cooling the heated mixture. As known to those skilled in the art of performing the relevant chemical reactions, the time and temperature profiles may be adjusted to provide an optimal balance of reactant and product solubility, reaction rate, avoidance of undesirable side reactions, and subsequent separability of desired products. Generally, the heating may be in the range of about 40 °C to about 85 °C, and the subsequent cooling may be in the range of about 0 °C to about 50 °C. As known to those skilled in the art of performing the relevant chemical reactions, the manufacturing methods may include many additional steps as needed to produce a desired extent of chemical reaction and subsequent separation and isolation ofdesired products efficiently in industrial settings. In addition, the manufacturing method may involve the use of many additional materials such as solvents, co-reactants, reaction rate modifiers, additives, carriers, separation agents, and other materials as will be apparent to one skilled in the art of practicing the relevant chemical reactions on an industrial scale.

[0049] EXAMPLES

[0050] Isomers magnolol and honokiol were used as raw materials to synthesize novel bio-based phthalonitrile compositions via a nucleophilic substitution reaction. Their curing behaviors, processability, thermal properties, and curing mechanism were evaluated.

[0051] Examples of monomeric precursor compositions, resin compositions, composite compositions, and ceramic compositions were prepared as follows:

[0052] Example 1. Preparation of Precursor A. 109.13 parts-by-weight (in grams) of 3',5-(5,5'-)diallyl-[1 ,1'-biphenyl]-2,4'-(2,2'-)diol (Magnolia extract), 141.89 parts-by-weight (in grams) of 3-nitrophthalonitrile, 125.49 parts-by-weight (in grams) of potassium carbonate, and 275 parts-by-weight (in grams) of acetonitrile were combined in a three-neck 2 Liter flask equipped with a condenser, thermocouple and a rubber septum under nitrogen, heated to 78°C and held at temperature with stirring for 8 hours. The reaction mixture was then cooled to 25°C and 450 parts-by-weight (in grams) of deionized water was slowly added, resulting in the formation of a solid precipitate. The precipitate was collected by filtration, and washed with deionized water until the pH = 7 of the filtrate was achieved, and dried in a forced air oven at 85°C, resulting in Precursor A (98% yield). The resulting monomer had a char yield of 77.5%, as determined by thermogravimetric analysis (TGA) under nitrogen at 1000°C at a 10°C / min scan rate.

[0053] Example 2. Preparation of Precursor B. 109.13 Parts-by-weight (in grams) of 3',5-(5,5'-)diallyl-[1 ,1'-biphenyl]-2,4'-(2,2'-)diol, 122.38 parts-by-weight (in grams) of 3-nitrophthalonitrile, 108.24 parts-by-weight (in grams) of potassium carbonate, and 275 parts-by-weight (in grams) of acetonitrile were combined in a three-neck 2 Liter flask equipped with a condenser, thermocouple and a rubber septum under nitrogen, heated to 78°C and held at temperature with stirring for 8 hours. The reaction mixture was then cooled to 25°C and 450 parts-by-weight (in grams) of deionized water was slowly added, resulting in the formation of a solidprecipitate. The precipitate was collected by filtration, and washed with deionized water until the pH = 7 of the filtrate was achieved, and dried in a forced air oven at 85°C, resulting in Precursor B.

[0054] Example 3. Preparation of Precursor C. 109.13 Parts-by-weight (in grams) of 3',5-diallyl-2,4'-dihydroxybiphenyl, 141.89 parts-by-weight (in grams) of 3-nitrophthalonitrile, 125.49 parts-by-weight (in grams) of potassium carbonate, and 275 parts-by-weight (in grams) of acetonitrile were combined in a three-neck 2 L flask equipped with a condenser, thermocouple and a rubber septum under nitrogen, heated to 78°C and held at temperature with stirring for 8 hours. The reaction mixture was then cooled to 25°C and 450 parts-by-weight (in grams) of deionized water was slowly added, resulting in the formation of a solid precipitate. The precipitate was collected by filtration, and washed with deionized water until the pH = 7 of the filtrate was achieved, and dried in a forced air oven at 85°C, resulting in Precursor C.

[0055] Example 4. Preparation of Comparative Monomer / Precursor D. 109.13 parts-by-weight (in grams) of 3',5-(5,5'-)diallyl-[1 , 1 '-biphenyl]-2,4'-(2,2'-)diol, 141.89 parts-by-weight (in grams) of 4-nitrophthalonitrile, 125.49 parts-by-weight (in grams) of potassium carbonate, and 275 parts-by-weight (in grams) of acetonitrile were combined in a three-neck 2 Liter flask equipped with a condenser, thermocouple and a rubber septum under nitrogen, heated to 78°C and held at temperature with stirring for 8 hours. The reaction mixture was then cooled to 25°C and 450 grams parts-by-weight (in grams) of deionized water was slowly added, resulting in the formation of a viscous liquid resinous precipitate. The precipitate was collected by decanting the aqueous phase, and washed with deionized water until the pH = 7 (aqueous phase) was achieved, and dried in a forced air oven at 85°C, resulting in Precursor D. The resulting monomer had a char yield of 71.6%, as determined by thermogravimetric analysis (TGA) under nitrogen at 1000°C at a 10°C / min scan rate. Notably, the char yield measured for the comparative monomer D based on 4- phthalonitrile moieties was significantly lower than that measured for the inventive monomer A comprising 3-phthalonitrile groups (Example 1).

[0056] Example 5. Preparation of Precursor E. 39.74 parts-by-weight (in grams) of 2,2'-bis(3-allyl-4-hydroxyphenyl)isopropylidene, 44.62 parts-by-weight (in grams) of 3-nitrophthalonitrile, 39.46 parts-by-weight (in grams) of potassium carbonate, and 110.5 parts-by-weight (in grams) of acetonitrile were combined in a three-neck 500 milliliter flask equipped with a condenser, thermocouple, and a rubberseptum under nitrogen, heated to 75°C and held at temperature with stirring for 8 hours. The reaction mixture was then cooled to 25°C and 165.75 parts-by-weight (in grams) of deionized water was slowly added. The solution was added to a separatory funnel and extracted with a water and ethyl acetate wash until the pH = 7 was achieved. The resulting resinous material was dried in a rotary evaporator to remove the excess ethyl acetate and then dried in a forced air oven at 85°C, resulting in Precursor E (89% yield). The resulting monomer had a char yield of 65.6%, as determined by thermogravimetric analysis (TGA) under nitrogen at 1000°C at a 10°C / min scan rate.

[0057] Example 6. Preparation of Comparative Precursor F. 39.74 parts- by-weight (in grams) of 2,2'-bis(3-allyl-4-hydroxyphenyl)isopropylidene, Diallylbisphenol A (DABPA), 44.62 parts-by-weight (in grams) of 4-nitrophthalonitrile, 39.46 parts-by-weight (in grams) of potassium carbonate, and 110.5 parts-by-weight (in grams) of acetonitrile were combined in a three-neck 500 milliliter flask equipped with a condenser, thermocouple, and a rubber septum under nitrogen, heated to 75°C and held at temperature with stirring for 8 hours. The reaction mixture was then cooled to 25°C and 165.75 parts-by-weight (in grams) of deionized water was slowly added. The solution was added to a separatory funnel and extracted with a water and ethyl acetate wash until the pH = 7 was achieved. The resulting resinous material was dried in a rotary evaporator to remove the excess ethyl acetate and then dried in a forced air oven at 85°C, resulting in Precursor F (85% yield). The resulting monomer had a char yield of 62.3%, as determined by thermogravimetric analysis (TGA) under nitrogen at 1000°C at a 10°C / min scan rate. Notably, the char yield measured for the comparative monomer F based on 4-phthalonitrile moieties was lower than that measured for the inventive monomer E comprising 3-phthalonitrile groups (Example 5).

[0058] Example 7. Preparation of Precursor G. 29.22 parts-by-weight (in grams) of 4,4'-sulfonylbis[2-(prop-2-en-1-yl)phenol], 30.63 parts-by-weight (in grams) of 3-nitrophthalon itrile, 27.09 parts-by-weight (in grams) of potassium carbonate, and 81 .25 parts-by-weight (in grams) of acetonitrile were combined in a three-neck 500 ml flask equipped with a condenser, thermocouple and a rubber septum under nitrogen, heated to 75°C and held at temperature with stirring for 8 hours. The reaction mixture was then cooled to 25°C and 121.86 grams parts-by-weight (in grams) of deionized water was slowly added, resulting in the formation of a solid precipitate. The precipitatewas collected by vacuum filtration, and washed with deionized water until the pH = 7 (aqueous phase) was achieved, and dried in a forced air oven at 85°C, resulting in Precursor G (81 % yield). The resulting monomer had a char yield of 71.6%, as determined by thermogravimetric analysis (TGA) under nitrogen at 1000°C at a 10°C / min scan rate.

[0059] Example 8. Preparation of Comparative Precursor H. Preparation of Precursor G. 35.07 parts-by-weight (in grams) of 4,4'-sulfonylbis[2-(prop-2-en-1- yl)phenol], 36.75 parts-by-weight (in grams) of 4-nitrophthalonitrile, 32.50 parts-by- weight (in grams) of potassium carbonate, and 97.5 parts-by-weight (in grams) of acetonitrile were combined in a three-neck 500 ml flask equipped with a condenser, thermocouple and a rubber septum under nitrogen, heated to 75°C and held at temperature with stirring for 8 hours. The reaction mixture was then cooled to 25°C and 200 grams parts-by-weight (in grams) of deionized water was slowly added, resulting in the formation of a viscous liquid resinous precipitate. The precipitate was collected by decanting the aqueous phase, and washed with deionized water until the pH = 7 (aqueous phase) was achieved, and dried in a forced air oven at 85°C, resulting in Precursor H (94.8% yield). The resulting monomer had a char yield of 68.2%, as determined by thermogravimetric analysis (TGA) under nitrogen at 1000°C at a 10°C / min scan rate. Notably, the char yield measured for the comparative monomer H based on 4-phthalonitrile moieties was lower than that measured for the inventive monomer G comprising 3-phthalonitrile groups (Example 7).

[0060] Example 9. Preparation of cured resin from Precursor A. 10,000 parts-by-weight (in grams) of Precursor A and 0.820 parts-by-weight (in grams) of 3',5- (5,5'-)diallyl-[1 , 1 '-biphenyl]-2,4'-(2,2'-)diol were combined in an aluminum dish, allowed to melt and mixed at 130°C on a hot plate for 5 minutes. The resulting mixture was then cured at 175°C for 6 h, 190°C for 6 h and 270°C at 8h. The resulting cured resin had a char yield of 76%, as determined by thermogravimetric analysis (TGA) under nitrogen at 1000°C. The resulting resin had a dry and wet (72 h boil test) Tgof 413°C, as determined by DMA (storage modulus).

[0061] Example 10. Preparation of a cured resin from Precursor C. 10.000 parts-by-weight (in grams) of Precursor C were placed in an aluminum dish, allowed to melt and mixed at 130°C on a hot plate for 5 minutes. The resulting material was then cured at 175°C for 6 h, 190°C for 6 h and 270°C at 8h. The resulting cured resin had a char yield of 78%, as determined by thermogravimetric analysis (TGA)under nitrogen at 1000°C. It is important to note that the char yield of the inventive 3- phthalonitrile honokiol derivative was higher than that of 75.4% reported for the 4- nitrophthalonitrile honokiol derivative [Weng, Z., et al. Polymer 226 (2021 ) 123814],

[0062] Example 11 . Preparation of a cured resin from Precursor B and a carbon filler. 6.000 parts-by-weight (in grams) of Precursor B and 4.000 parts-by- weight (in grams) milled carbon fiber were placed in an aluminum dish, allowed to melt and mixed at 130°C on a hot plate for 5 minutes. The resulting material was then cured at initially at 150 °C for 2 hours and 215 °C for 6 hours. A freestanding post cure was performed for 4 hours at 350 °C. The resulting cured resin had a char yield of 84.3%, as determined by thermogravimetric analysis (TGA). The TGA test conditions included a constant temperature ramp rate of 10 °C / min from room temperature to 1000°C.

[0063] Example 12. Preparation of a carbon composite panel from Precursor A. 50.000 parts-by-weight (in grams) of Precursor A and 4.100 parts-by- weight (in grams) of 3',5-(5,5'-)diallyl-[1 , 1 '-biphenyl]-2,4'-(2,2'-)diol were mixed in a mortar and pestle to prepare fine powder. Solid resin samples of approximately 5.440 parts-by-weight (in grams) were then prepared by pouring the molten resin into aluminum weighing dishes and allowing to cool to room temperature. Six 7x7 inch plies of T300 carbon fiber fabric weighing about 6.8 parts-by-weight (in grams) each were cut (4 plies at 0 degrees and 2 at 45) and used to lay up a 6-ply panel [90, +45, 90, 0, -45, 0] by spreading approximately 5.440 parts-by-weight (in grams) of the prepared resin powder evenly across each ply. The resulting part was enveloped in a solid release film with a strip of fiberglass on one edge. This assembly along with a vacuum port was then vacuum bagged (Kapton® brand polyimide film) in the manner typical of out-of-autoclave composite processing and placed into an oven preheated to 125°C. The resin powder was allowed to melt, approximately 27.5 inHg vacuum was applied to the assembly and a squeegee tool was used to wet out the plies more evenly. The part was then allowed to dwell at 125°C for 1 h, followed by a ramp to 176°C at 2°C / min, dwell at 176°C for 6h, and ramp to 30°C at 2°C / min. The vacuum bag and other external materials were then removed from the laminate, and the laminate subjected to the following post cure cycle: ramp to 270°C at 2°C / min, dwell at 270°C for 8h, and ramp to 30°C at 2°C / min.

[0064] Example 13. Preparation of one-dimensional carbon composite filament from Precursor B. Precursor B was allowed to melt at 150°C, held at temperature, and a filament (HexTow® IM10-12kGP) was pulled through the moltenmonomer bath resulting in a resin impregnated carbon filament with the resin content of ca. 30 wt%. A respective composite tubular shape was then prepared by utilizing an AXIS Model 4X-23 filament winder. The initial cure of the part was performed by ramping to 165C at 1 °C / min, with a 12 hour hold at 165 °C and ramp down to 35 °C at 1 °C / min before removing from the oven. The heat shrink tape and flashbreaker tape materials were then removed from the part and a second cure was performed by ramping to 250 °C at 1 °C / min, with a 12 hour hold at 250 °C, and ramp down to 35 °C at 1 °C / min before removing from the oven.

[0065] Unless otherwise expressly indicated herein, all numerical values indicating mechanical / thermal properties, compositional percentages, dimensions and / or tolerances, or other characteristics are to be understood as modified by the word “about” or “approximately” in describing the scope of the present disclosure. This modification is desired for various reasons including industrial practice, material, manufacturing, and assembly tolerances, and testing capability.

[0066] As used herein, the phrase at least one of A, B, and C should be construed to mean a logical (A OR B OR C), using a non-exclusive logical OR, and should not be construed to mean “at least one of A, at least one of B, and at least one of C.”

[0067] Various compositions / elements of the present disclosure may be presented in a range format, which should not be construed as limiting the scope of the present disclosure. The description of a range should be considered to have specifically disclosed all the possible subranges as well as individual numerical values within that range. For example, description of a range such as from 1 to 10 should be considered to have specifically disclosed subranges such as, by way of example, from 1 to 5, from 2 to 7, from 1 to 9, from 3 to 4, and so on, as well as individual target values within the range, for example, 1 , 2, 3, 4, 5, and 6, among others. Therefore, the disclosure of a given range should be construed to include all values within the range even if not explicitly recited.

[0068] The description of the disclosure is merely exemplary in nature and, thus, variations that do not depart from the substance of the disclosure are intended to be within the scope of the disclosure. Such variations are not to be regarded as a departure from the spirit and scope of the disclosure.

Claims

CLAIMSWhat is claimed is:

1. A composition comprising at least one bonded alkene-terminated polyphenol reacted with 3-phthalonitrile.

2. The composition according to Claim 1 , wherein the at least one bonded alkene-terminated polyphenol is sterically hindered.

3. The composition according to Claim 1 , wherein a functional group of the at least one bonded alkene-terminated polyphenol is an allyl group.

4. The composition according to Claim 1 , wherein the at least one bonded alkene-terminated polyphenol comprises magnolol, honokiol, or a mixture of magnolol and honokiol.

5. The composition according to Claim 4, wherein at least one of the magnolol, the honokiol, or the mixture of magnolol and honokiol comprises magnolia species extracts.

6. The composition according to Claim 1 , wherein the at least one bonded alkene-terminated polyphenol comprises 2,2'-bis(3-allyl-4- hydroxyphenyl)isopropylidene and / or 4,4’-sulfonylbis[2-(prop-2-en-1 -yl)phenol].

7. The composition according to Claim 1 , wherein the 3-phthalonitrile comprises 3-nitrophthalonitrile.

8. The composition according to Claim 1 , wherein the at least one bonded alkene-terminated polyphenol is reacted with less than about 0.95 equivalents of 3- phthalonitrile.

9. The composition according to Claim 1 , wherein the at least one bonded alkene-terminated polyphenol is further reacted with a molecule group selected from the group consisting of 4-nitrophthalonitrile, allyl and propargyl halides, alkyl halides,alkenyl halides, alkynyl halides, aryl halides, benzyl halides, aryl dihalides, and alkyl dihalides.

10. The composition according to Claim 1 , wherein the at least one bonded alkene-terminated polyphenol comprises magnolol and honokiol, and wherein an amount of the magnolol is from 40 to 60 parts by weight, and an amount of the honokiol is in an amount from 40 to 60 parts by weight.

11. The composition according to Claim 1 , further comprising at least one substance selected from the group consisting of magnolia 4-nitrophthalonitrile adducts, phenolic adducts of 3-nitrophthalonitrile and / or 4-nitrophthalonitrile, propargyl ethers, epoxies, benzoxazines, maleimides, and cyanate esters.

12. The composition according to Claim 1 , further comprising at least one additive selected from the group consisting of phenolic and amino-functionalized compounds, transition metal catalysts, and carbon and inorganic micro- and nanostructures.

13. A partially or fully cured polymer comprising the composition according to any of the preceding claims.

14. The partially or fully cured polymer according to Claim 13, wherein the partially or fully cured polymer has a char yield of at least about 75%.

15. The partially or fully cured polymer according to Claim 13, wherein the partially or fully cured polymer contains residual unreacted polymerizable groups.

16. An article comprising the partially or fully cured polymer according to any of Claims 13-15.

17. A ceramic and / or graphitic composite material comprising the partially or fully cured polymer according to Claim 13, wherein the ceramic and / or graphitic composite material comprises a ceramic that has been pyrolized, carbonized, and / or graphitized.

18. An article comprising the ceramic and / or graphitic composite material according to Claim 17.

19. A composite prepreg material comprising the composition according to any of Claims 1-15.

20. A reinforced composite material comprising the composition according to any of Claims 1-15.

21. A filament material comprising the composition according to any of Claims 1-15.

22. A method of manufacturing the composition according to Claims 1-12, wherein the at least one bonded alkene-terminated polyphenol is chemically reacted with 3-phthalon itrile to form a mixture.

23. The method according to Claim 22, further comprising: (a) heating the mixture, the mixture comprising at least one bonded alkene-terminated, polyphenol and 3-nitrophthalonitrile, to a temperature from about 20°C to about 120°C and (b) cooling the mixture to a temperature from about -20°C to 100°C to form a precipitate.

24. The method according Claim 22, wherein the mixture comprises at least one bonded alkene-terminated, polyphenol and 3-nitrophthalonitrile, and the mixture is heated to a temperature from about 40°C to about 85°C, and cooled to a temperature from about 0°C to 50°C to form a precipitate.

25. The method according to Claim 22, wherein the mixture comprises at least one bonded alkene-terminated, polyphenol and 3-nitrophthalonitrile, and the mixture is heated to a temperature from about 60°C to about 80°C, and cooled to a temperature from about 10°C to 40°C to form a precipitate.

26. A method of manufacturing the partially or fully cured polymer of Claim 13, wherein the partially or fully cured polymer is reacted without use of a curing agent.